In a standard shuttleless loom a weft yarn is pulled from a supply spool by a mechanical feeder and is fed thereby to an injection nozzle that is directed crosswise through a shed formed between upper and lower groups of warp yarns. Inside the shed the yarn is guided along a passage formed by the teeth of a confining comb mounted on a sley along with the beating comb or reed. The yarn is moved the entire weft-wise width of the fabric by relay nozzles spaced along the shed and pressurized sequentially. At the downstream edge of the goods the yarn is trapped by a weft-yarn aspirator and held thereby.
It is standard to provide a pair of such supplies and feeders. This allows weaving to continue with a yarn from a second supply when the first supply runs out or jams, and also serves for color change if desired. As described in European patent application 195,469 filed by J. Waelkens based on a Belgian priority of 24 Sept. 1985 two separate weft-filament feeders are provided adjacent a common injection nozzle, the latter being carried on the beating-in comb for warpwise movement therewith. There is no disclosure of how the new yarn is threaded into the injection nozzle on switchover.
European patent application 291,486 filed by J. Tacq based on a Belgian priority of 17 Nov. 1988 has a similar pair of feeders and a single injection nozzle. Here, however, each of the feeders, which each comprise a yarn package and payout device having a feed nozzle, has an output aligned at an acute angle with the intake of the injection nozzle. To make it possible to thread a new filament into the injection nozzle despite the turbulence of the various air currents created in such a pneumatic delivery system, each of the feeders can be moved to a position very close to the upstream end of the injection nozzle for feeding thereto a new filament. Such a system is fairly complex and involves moving around a substantial amount of delicate equipment at each filament change.